Absorbent articles such as disposable diapers, incontinent pads and catamenial napkins generally include an absorbent core that has a multiplicity of components so as to improve the absorption and retention characteristics of the absorbent core. Recent advances in the field of absorbent cores have developed a relatively new class of materials known as superabsorbent polymers or absorbent gelling materials (AGM's) which can be incorporated along with absorbent fibrous materials to form improved absorbent cores. Multi-component absorbent cores wherein at least one component consists solely of hydrophillic fibers and at least one component consists of a substantially uniform combination of hydrophillic fibers and particular amounts of discrete particles of absorbent gelling materials, have been found to be especially efficient and effective in absorbing and containing bodily fluids.
Several difficulties are encountered in manufacturing absorbent cores having a multiplicity of components especially wherein at least one of the components contains discrete particles of an absorbent gelling material. While such absorbent cores can be manufactured by two or more separate and complete core-making apparatus, the costs of providing such a system is prohibitive. Accordingly, it would be advantageous to provide a single apparatus for forming fibrous webs having a multiplicity of components.
In addition, because absorbent gelling materials are generally significantly more expensive than readily available hydrophillic fiber materials (e.g. cellulose fibers), it would be advantageous to reduce the quantity of absorbent gelling materials in the core by not spreading absorbent gelling materials throughout the entire core but by targeting them in specific areas or components of the absorbent core. However, with conventional airlaying apparatus, it is difficult to limit absorbent gelling materials to only one component. Thus, it would be advantageous to provide an apparatus and method for forming an absorbent core having a multiplicity of components wherein only one of the components contains a small amount of AGM in the critical areas rather than throughout the entire absorbent core.
One solution to providing an apparatus and method for forming such an absorbent core is to split a column of fibers formed by a disintegrator into individual streams of fibers which can be individually directed to different airlaying apparatus or different portions of the same airlaying apparatus. However, a major disadvantage of attempting to split a column of fibers is that the fibers tend to clump and accumulate around the splitting mechanism. In particular, when a fiber column is split by mechanical means such as a doctor's edge or dividing plate or diverting vane, the clumping phenomenon is especially acute. Thus it would be advantageous to provide an apparatus for and method of splitting a column of fibers into a multiplicity of fiber streams while reducing the amount of fiber clumping.
Accordingly, it is an object of the present invention to provide an apparatus for and method of splitting a fiber column into a multiplicity of fiber streams.
It is also an object of the present invention to minimize fiber clumping during the splitting of the fiber column.
It is a further object of the present invention to provide an apparatus for providing multiple, independent streams of air-entrained fibers.